The objective of this application is for Wayne State University (WSU) to continue as a Maternal-Fetal Medicine Unit (MFMU) network site. With respect to academic productivity in the MFMU network WSU is ranked in the middle for patient recruitment and retention/completion, and 5.5 in adherence/data quality, with 100% 12 and 24 months infant follow-up in the TSH trial. WSU contributed a disproportionately high number (21%) of African American patients enrolled, by the 14 MFMU centers, to the 2 RCTs initiated in the current funding cycle. The WSU Principal Investigator participated in Committees and Subcommittees, and contributed to research development and design of the TSH protocol. WSU investigators submitted 10 proposals and first authored 6 MFMU publications. The WSU MFMU team achieved the objectives with highly qualified leadership that has knowledge and experience in research design, and collaboration in multicenter randomized clinical trials, experienced research staff, in the presence of extensive research infrastructure. The WSU Principal Investigator increased his protected time to 50%, dedicated to MFMU related activities, and is adding 2 sites, which will increase the patient population available at WSU for MFMU recruitment by 70% to 9418 deliveries/year. Health care providers in the 3 sites are required to provide access to all patients for screening and enrollment to research studies. Maternal-fetal staff, including 13 faculty and 7 fellows, are very productive with 265 peer-reviewed publications, and contribution to 11 non-MFMU studies of cooperative or multicenter design. WSU has been a center in the NICHD Neonatal Research Network since 1986. The large high quality perinatal data system assisted in writing this application, and has a unique notification system for MFMU research nurses of MFMU enrolled patients. Special strengths include faculty with experience in research administration, the Mott center for research, and the NICHD Perinatology Research Branch. The central hypothesis of our concept proposal is that treatment with azithromycin will reduce the risk of spontaneous preterm birth (SPTB) among women that (Uu) undergo mid-trimester genetic amniocentesis for clinical indications, and have Ureaplasma urealyticum detected in amniotic fluid, by polymerase chain reaction (PCR). The concept proposal is a randomized, double-blind, placebo controlled, multicenter trial. The proposed research is innovative. Results could change practice, by providing a strong foundation for routine PCR testing of AF obtained during amniocentesis for clinical indications, administration of antibiotics, and reduction in PTB. The research proposal is expected to reduce PTB and improve the health of pregnant women their neonates.